Shore erosion is a continuing problem along many shorelines including those of the oceans as well as the Great Lakes. During storms or rough water, beaches can literally disappear. Many efforts have been made to prevent this erosion ranging from breakwaters to offshore reefs. One particularly effective offshore reef assembly is shown in my prior U.S. Pat. No. 4,341,489.
The offshore reef assembly of this patent uses a series of substantially vertical supports. Blocks in the form of frustums of pyramids or cones are stacked on the vertical supports in an offset fashion to form with the inclined side faces of the blocks laterally spaced yet facing alternating ribs and grooves. The staggered faces on the blocks on the vertical supports dissipate the vertical wave action causing sand and other particulates in the water to drop out and be deposited on the bottom around the reef assembly.
One major problem with such offshore reef assembly is the complexity of the structure having a substantial number of parts, but also the difficulty of assembly offshore. A difficulty is that the parts may not be substantially preassembled on shore. The reef assembly literally has to be assembled offshore requiring an inordinate amount of expensive barge and crane time.